An image reading system such as a facsimile machine and a copy machine has an operation panel operated by a user. The operation panel having an improved operability is needed and also it has to be designed with universal design.
In order to improve operability of the operation panel, a mechanism in which a tilt angle of the operation panel can be adjusted to suit preference of the user is proposed.
For example, Japanese Patent Application Laid-Open No. 2003-259048 discloses a support device for supporting a display panel which includes a rotary connection portion and an elastic member. If the display panel is set with a predetermined posture, an amount of deformation of the elastic member decreases. That is, deformation of the elastic member in the predetermined posture is smaller than the deformation before and after this posture. Accordingly, the display panel is kept in the predetermined posture.
Japanese Patent Application Laid-Open No. 2007-334157 proposes an image forming device in which a posture of an operation panel can be adjusted at multiple postures by a posture adjustment mechanism.
The posture adjustment mechanism includes a plurality of lock pins concentrically arranged around a rotating shaft and an engagement member composed of an elastic material engaging with the lock pins. One of the lock pin and the engagement member is provided on a main-body side of the image forming device, and the other is provided on an operation panel.
Accordingly, when the posture of the operation panel is changed, the engagement member is largely elastically deformed to engage with the lock pin. When the engagement member engages with the lock pin, an amount of elastic deformation of the engagement member becomes small. Therefore, the posture of the operation panel is kept as it is.
Japanese Patent Application Laid-Open No. 2001-146874 proposes a tilt mechanism in which a torque value changes when a display portion rotates.
The tilt mechanism includes a fixed side bracket having a rotation center hole and an elongate hole that is concentric with respect to the rotation center hole, and a rotation side bracket in which a shaft and a sub-shaft are provided. A plate thickness of the surrounding fixed side bracket of the elongate hole changes with position.
The shaft is inserted into the rotation center hole and the sub-shaft is inserted into the elongate hole. The rotation side bracket is fixed to the fixed side bracket by screwing a nut on the shaft and the sub-shaft with a friction body composed of a spring washer.
Therefore, when the rotation side bracket rotates with respect to the fixed side bracket, the torque value changes according to a plate thickness of the elongate hole part.
Japanese Patent Application Laid-Open No. 1995-319396 proposes a tilt mechanism in which a movable part of an operation display portion or the like on which external force or own weight acts can be firmly fixed and supported to a main-body at a desired angle.
The tilt mechanism includes a screw shaft, a spring, a joint part of the main-body and the joint part of the operation display. One end of the screw shaft is screwed into the main-body side, and the other end forms a knob.
An engagement slot is formed on a contact face between the joint part of the main-body and the joint part of the operation display. The joint part of the operation display is fixed to the operation panel.
The screw shaft is screwed into the main-body side while penetrating the spring, the joint part of the main-body and the joint part of the operation display.
According to a tilt degree of the joint part of the operation display for the joint part of the main-body, an engagement state of the engagement slot on both changes. And the deformation of the spring becomes the smallest when the engagement slot on both has geared completely.
Because the deformation of the spring becomes the smallest when the engagement slot on both has geared completely, the display panel is held at the posture at this time.
Above-mentioned patent documents describe that the posture of the operation panel can be set optionally and operability thereof is improved.
However, a breakage of the parts and degrading of quality might arise by the impact generated when changing the posture of the operation panel.